Gas piston operated breechblock lock



March 21, 1950 B. MAILLARD GAS PISTON OPERATED BREECH BLOCK LOCK Filed July 3, 1947 Ilr III; Il

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NN WW Illli Patented Mar. 21, 1959 GAS PISTON GPERAT LOCK Bernard' Maillard', Geneva, Switzerland', assigner tof Soc'etyr fBrevets Aero-Mecaniques S. A., Geneva, Switzerland, ai society' of France Application Julys, 1947, sentirne.. 7-5s=,815 In Switzerland July 13, 1946 (Cli SSV-41911)' 3 Claims;

The invention relates. to.' automatic rearms including a breechblock slidable in. abreech casing and cooperating with a system movable longitudinally with respect to said breechblock. to Y ensure, at the end off' its frontward stroke, temporary locking' of the hreechblbck with respect to the breech casing.

The present. invention relates to arms of this kind inv which the movable system in question is controlled. through. driving. means carriedby the barrel' and. operated`v by powder' gases' from' said barrel, said" means acting upon the movable system through the' intermediate of' oneA or several transmission systems each constituted by a single push-piece slidable in' a corresponding housing provided for. this purpose in a' portion of the firearm' rigid" with the'breecn' casing.

This construction permits of easily detaching the barrel' from' the' breech' casing but' itv involves disturbances in the: workingofthebreech mechanism. due to oscillations of' the" transmission systems caused' by rebounding. thereof between the movable system and the' driving means above referred to.

The object of" the present' invention' is" to' ob'- viate this drawback.

For this purpose each transmission system is constituted' by at" least two independent pushpieces disposed end; to end' and' freely" slidable with respect tothe' breech casing', whereby the rebounding oscillations' are quickly dampedl A preferred embodiment ofn my invention will be hereinafter described' withI reference to' the accompanying, drawings, given merely by' way of example, and in whicht' Fig. 1 is an elevation view, partly in section, of an automatic. firearmY made vaccording to the invention;

Fig; 2 is a hori'zonta'l section onA theline'II-I'I' of rFig. 3;

Figs'. 3 and. 4 are' cross sectional views respectively on the lines III-III and'IV'Y-IV'of Fig; 1.;

Fig. 5 is a plan view of the" locking; piece and ofthe portions ofthe breech casing withwhi'c'h it cooperates.

The automatic firearm shown. by this drawing includes, at the rearv of a barrel I0, a breech casing I'I in which is slid'ably mounted a breech system constituted by" the three following elements: a breechl'olock I2, a locking piece I3- intended! toV lock the' bre'echbIoc'I'iv with respect to the breech casing. wheny a` shot is red and a reciprocating system. intended' temporarily to keep the locking piece I3' the breech" block locking position. This reciprocating system is consti'-4 2. tut'ed" by two sliding' plates' I4" connected together by' a key f5' and' sl'idable longitudinally with respect' tothe' breech casingT` I'I. Key I5? extends through an' elongatedl` slotv I'6 provided in' the breech block and" carriesa` firingV pin I1 slidable in an' axial bore` I8' acting also` as` housing for a recnperatorspring' I9". The displacement' of slid'- ing plates |14' with respect to' breech casing. I'I is-limited' by the' length of' slot I6. Percussion springs` 2U, interposed' between' sliding plates I4 and' lugs integral with the vbreechbloclr, urge' said sliding plates I4" forwardly with respect to` the breechblock'. Lockingv piece' I3" is housed inv a recess-provided in the lowerA part of the breech'- block. At its front-endv it includes a cylindrical surface" 22, engaged' in a housing" 23 of the same shape provided' in the breech casing and' which acts as a hinge. A't its' upper part; the locking piece isp'rovided with projections 24" intended to engage notches 25 cut in' the' bottom of sliding plates I4. Its rear iace 2liY is adapted to Vco'- operate; in' the lock-'ed' position thereof, with a shoulder' 2'1" provided in' a cross piece 28' rigid with' the breech casing II.

Locking" piece' f3' also includes two'latera'l" pro` jections 2ey (shown on" Fig. 5T); The frontp'art of' thesez projections forms iricliriedT surfaces 3|) located' opposite" inclined surfaces 3I disposed on two' parts 32' rigid withthe' breech' casing. Inclined surfaces 30V and' 3 I are intended tocome into contact a s'hort time-befre'the breechblock reaches the end' of its'frontwardlstroke, so` as` suddenly to drive the rear part of the'locking' piece downwardly, the'front part remaining heldin the hinge housing'. 23'. The locking piece then engages', through its' face' 26; shoulder 21'. It is heldiin' this position by plates' I4", which slide on the top thereof as" theykeep' moving' forward to ensure' percussion.

The piece that controls i the rearward displacementsf of" sliding plates I4 to` release the locking' pieceafter' a'shot has been' redis constituted by a rod'v 33 the front end of which' forms a cylinder` 342' cooperating' withv a iixed piston 35'. This cylinder communicates with the barrel bore' throughA thei intermediate' of a channel 36 pro'- vided in the' piston and of" a vent' 3T. Rod 33", which! is hollow, is guided at its' rear' end by a x'ed spindle 3'8` rigid with barrel IU; It is'subjje'cted'to the action of a spring'39, housed'thereim, which urges` it in the' frontward" direction. The

rear part of the` rod includes an' enlarged' portion' 4'U'wlii`ch is' astri'de barrel I0.

After a' shot'has'b'e'en' fired', rod' 33 produces.k

a' rearward movement of'sliding plates r4 to release the locking piece and to permit rearward movement of the breechblock. For constructional reasons and in order to permit of easily taking the barrel apart, the movement of rod 33 is not to be transmitted to the sliding parts through pieces rigid with one of these elements. Use is made of independent transmission systems each constituted by two pairs of push-pieces il and 42 unconnected together and freely slidable in two cylindrical housings t3 provided in breech casing II. Push-pieces III are intended to enter into contact with part 40, whereas push-pieces 42 are intended to enter into contact with the front ends of sliding plates I4.

The operation is as follows. In locked position, breechblock I2 is kept in its front position by locking piece I3, sliding plates Ill keep said locking piece in this position and also at the end of their frontward stroke, cause the firing pin to strike the cartridge. Rod 33 is kept in forward position by spring 39 and push-pieces Il and i2 have but little play left for them between part d and the front ends of sliding plates Ill. As soon as the projectile has moved past vent 3l, gases penetrate into channel 36 and push rod 33 rearwardly. Through push-pieces Lil and LIZ, this rod causes sliding plates I4 to move rearwardly with respect to the breechblock, thus releasing locking piece I3. Under the effect of the pressure it undergoes from the cartridge case, the breechblock moves backward and pushes said locking piece I3 upwardly. Rod 33 automatically comes back to its frontward position under the action of spring 39, but push-pieces lil ,and ft2 remain stationary in their rear position until sliding plates I4, in the course of their frontward return movement, on the next closing of the breechblock strike them in the forward direction.

Experience taught that, if each transmission system between part d and one of the sliding plates Ill is constituted by a single push-piece instead of several independent push-pieces placed end to end,- the forward return movement of sliding parts Ill is seriously interfered with by successive reboundings of this single push-piece.

As a matter of fact, when there is a single pushpiece, it is driven forwardly by the corresponding sliding plate, rebounds on part d, rebounds again on the sliding plate, and so on, and thus performs a series of reciprocating movements which brake the sliding plate and risk reducing the velocity thereof so much that the firing pin fails to work.

In order to obviate this drawback in the firearm according to the present invention, each transmission means between rod 33 and a sliding plate I4 is constituted by a series of push-pieces independent from one another diposed in the same housing. Owing to this arrangement, the forward movement of sliding plates M is much less influenced by reboundings of the push-pieces.

As a matter of fact, when one of the rear pushpieces 42 is driven frontwardly by the corresponding sliding plate lli, it is itself braked by the impulse it must impart to the front push-piece di. The latter is driven forwardly, rebounds on part 40, and again strikes the rear push-piece 52. The shock between these two push-pieces has for its effect greatly to reduce their living force. While push-piece 4I starts back in the forward direction, push-piece i2 keeps moving with a reduced velocity. Push-piece d2 may possibly come once more into contact with'the corresponding sliding plate Ill but in view of the low velocity and small weight of this push-piece, this new shock will have but little iniiuence upon the velocity of the sliding plate. Consequently owing to the fact that the transmission between sliding parts I4 and part lili is ensured not by a single push-piece but by a series of push-pieces of smaller weight which mutually` strike one another, reboundings between sliding plates Ill and part lil) are reduced to a minimum and have but a negligible influence upon the velocity of the sliding plates.

It is clear that each series may include a greater number of push-pieces and that, in a given series, the push-pieces may be of different respective dimensions.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and eiiicient embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts Without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

l. In an automatic firearm, the combination of a barrel, a breech casing xed to said barrel, a breechblock slidable longitudinally in said breech casing, means for locking said breechblock in closed position with respect to said breech basing, said means including at least one piece longitudinally movable with respect to said breechblock, elastic means urging said piece toward the position thereof with respect to said breechblock that corresponds to locking of the breechblock in the breech casing, means operative by powder gases from said barrel for driving said piece away from said position upon firing of a shot, said last mentioned means including a driving part carried by said barrel, operative by powder gases, and at least two push pieces mounted end to end, longitudinally guided in said breech casing and freely slidable therein between said driving part and said sliding piece to transmit the action of said driving part to said sliding piece.

2. In an automatic firearm, the combination of a barrel, a breech casing fixed to said barrel, a breechblock slidable longitudinally in said breech casing, means for locking said breechblock in closed position with respect to said breech casing, said means including two pieces longitudinally movable with respect to said breechblock arranged symmetrically on either side of the longitudinal middle plane of said barrel, elastic means urging said pieces toward the position thereof with respect to said breechblock that corresponds to locking of the breechblock in the breech casing, means operative by powder gases from said barrel for driving said piece away from said position upon ring of a shot, said last mentioned means including a driving part carried by said barrel, operative by powder gases, and at least two push pieces, mounted end to end, longitudinally guided in said breech basing and freely slidable therein between lsaid driving part and each of said sliding pieces to transmit the action of said driving part to each of said sliding pieces.

3. In an automatic firearm, the combination of a barrel, a breech casing fixed to said barrel, a breechblock slidable longitudinally in said breech casing, means for locking said breechblock in closed position with respect to said breech casing, said means including a locking member movably connected with said breechblock and fixed, with respect to said breech casing in locking position, at least one piece longitudinally slidable to a limited extent with respect to said breechblock adapted, in the course of its forward motion, to bring said member into locking position and to keep it in said position, elastic means urging said piece forwardly with respect to said breech casing. means operative by powder gases from said barrel for driving said piece rearwardly upon firing of a shot, said last mentioned means including a driving part carried by said barrel, operative by powder gases, and at least two push pieces mounted end to end longitudinally guided in said breech casing and freely slidable therein between said driving part and said sliding piece to transmit the action of said driving part to said sliding piece.

BERNARD MAILLARD.

REFERENCES CITED yThe following references are of record in the file of this patent: 

